The present invention relates to safety devices for welding and more particularly to a safety device for gas welding.
There are known safety devices installed on the side of such an inflammable gas as acetylene gas for use in welding. When oxygen gas or a mixture of oxygen gas and acetylene gas flows backward to the acetylene gas side, whether the gas is in the burning state or not, the known practice is to warn the operator of the counter-flow by means of a counter-flow indicating mark while blocking the counter-flow of the gas.
Although the counter-flow itself can be made known by means of the counter-flow indicating mark in such a safety device for gas welding, there still exists much inconvenience in that the normal-flow condition is left unknown.